The war’s second year saw the front lines harden, along with the combatants’ resolve.Trench lines dug for the winter became permanent, while offensives throughout the year did little but add to the death toll. As the war consumed men and resources, both sides shifted their economies to full wartime production.
In January, U.S. President Woodrow Wilson offered to mediate peace talks.No one was interested; both sides were determined that their 1914 losses would not be in vain, and both believed they would win the war.
France launched a February offensive that achieved nothing, but cost 250,000 casualties.That same month, Germany began unrestricted submarine warfare, attacking all merchant ships in the waters around Great Britain without warning -- even those from neutral nations.The Germans responded to protests by pointing to Britain’s naval blockade and complaining of a double standard.
The combatants introduced new ways to inflict violence.The Germans introduced poison gas on the Western Front during the Battle of Ypres in April.InMay, German zeppelins (airships) over London carried out the first aerial bombing of civilians in history.
Also in May, a German U-boat sank the British ocean liner Lusitania, resulting in 1,200 deaths, including 128 Americans. In response to U.S. outrage, Germany halted unrestricted submarine warfare.
Over the course of the year, the French tried and failed to push the Germans out of their territory. The British built up a massive army to join the French in the front lines.The Germans held their ground while making progress on the Eastern Front.1915 closed with the Western Front locked in trench warfare and stalemate -- but with both sides confident of winning the war in 1916.